• 한국양식학회지
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• 제20권2호
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• pp.81-84
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• 2007

We studied two research items that can be undetermined issues in the artificial seed production of the Japanese scallops, Patinopecten yessoensis, batch-specific quality of the reproductive outputs and nursery acclimation, in the embayed waters of Yangyang, Gangwon, Korea. The first batch of the spawner showed better results in terms of survival, growth, and resistance against parasitic ciliate infection over the second batch that was obtained in 5 days after first batch from the same spawner. The early attached spats directly placed in the farming ground (the unacclimated) were resistant against the water current of the open environment, by showing survival of about 80% for a month, a normal survival compared with other results. However, the spat survival during the nursery acclimation was significantly lowered in comparison with that in the unacclimated condition (P<0.01). We discussed the research results of the two items, particularly focusing on their availability for mass seed production for aquaculture in the Korean coastal waters of the East Sea (Sea of Japan).

• ALGAE
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• 제32권4호
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• pp.309-324
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• 2017

Recently, the heterotrophic nanoflagellate Katablepharis japonica has been reported to feed on diverse red-tide species and contribute to the decline of red tides. However, if there are effective predators feeding on K. japonica, its effect on red tide dynamics may be reduced. To investigate potential effective protist predators of K. japonica, feeding by the engulfment-feeding heterotrophic dinoflagellates (HTDs) Oxyrrhis marina, Gyrodinium dominans, Gyrodinium moestrupii, Polykrikos kofoidii, and Noctiluca scintillans, the peduncle-feeding HTDs Luciella masanensis and Pfiesteria piscicida, the pallium-feeding HTD Oblea rotunda, and the naked ciliates Strombidium sp. (approximately $20{\mu}m$ in cell length), Pelagostrobilidium sp., and Miamiensis sp. on K. japonica was explored. We found that none of these heterotrophic protists fed on actively swimming cells of K. japonica. However, O. marina, G. dominans, L. masanensis, and P. piscicida were able to feed on heat-killed K. japonica. Thus, actively swimming behavior of K. japonica may affect feeding by these heterotrophic protists on K. japonica. To the contrary, K. japonica was able to feed on O. marina, P. kofoidii, O. rotunda, Miamiensis sp., Pelagostrobilidium sp., and Strombidium sp. However, the specific growth rates of O. marina did not differ significantly among nine different K. japonica concentrations. Thus, K. japonica may not affect growth of O. marina. Our findings suggest that the effect of predation by heterotrophic protists on K. japonica might be negligible, and thus, the effect of grazing by K. japonica on populations of red-tide species may not be reduced by mortality due to predation by protists.

• 식물분류학회지
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• 제48권1호
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• pp.37-42
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• 2018

백두산에서 양지꽃속의 신종인 백두산양지꽃(Potentilla baekdusanensis M. Kim)을 새로이 발견하여 기재하였다. 백두산양지꽃은 잎이 우상복엽이며 엽신과 엽병에 털이 있고 3개의 상부 소엽이 하부 소엽보다 크며 포복경이 없어 양지꽃과 유사하다. 그러나 백두산양지꽃은 식물체가 소형이고 짧은 누운 털이 있으며 근생엽이 7장의 소엽으로 이루어졌고 하부 소엽이 작으며 소엽가장자리에 털이 없고 꽃잎 기부에 황적색의 무늬가 있다. 반면에, 양지꽃은 식물체가 대형이고 긴 곧은 털이 밀생하며 근생엽이 9-15장의 소엽으로 이루어졌고 하부 소엽이 크며 소엽가장자리에 긴털이 밀생하고 꽃잎 기부에 황적색의 무늬가 없는 점에서 두 종이 뚜렷하게 차이가 난다.

• 생태와환경
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• 제38권4호통권114호
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• pp.494-502
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• 2005

녹조대발생의 원인종인 남조 Microcystis aeruginosa와 규조 Stephanodiscus hantzschii 에 대한 살조 및 섭식능을 갖는 박테리아 및 섬모충을 각각 단독 및 혼합처리하고 살조능을 비교하였다. 먼저 남조 M. aeruginosa에 대하여 살조세균 Streptomyces neyagawensis와 섬모충 Stentor roeselii를단독 및 혼합처리한 결과, 각각의 단독처리가 혼합처리보다 더 높은 살조능을 나타내는 두 생물제재의 길항적 살조효과를 나타냈다. 또한 규조 S. hantzschii 에 대해 살조능을 갖는 박테리아 P seudomonas putida와 S. roeselii를 전과 동일한 방법으로 단독 및 혼합처리하여 결과를 비교하였다. 전 실험과는 다르게 두 생물제재의 혼합처리가 단독처리보다 더 높은 살조능을 보이는 두 생물제재의 상승적 살조효과를 나타냈다. 이러한 결과들은 녹조 제어를 위한 생물제재의 적용시 유용하게 이용될 것이며, 다양한 생물제재를 이용함으로서 수중생태계의 혼란을 초l소화시킬 수 있을 것으로 사료되었다.

• 한국어병학회지
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• 제16권1호
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• pp.13-21
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• 2003

The infection characteristics with scuticociliates at on-land rearing farms and hatcheries of flounder, Paralithys olivaceus was investigated during the year of 2001 by juvenile infection routes. When culture tanks for living food organisms such as chlorella, rotifer, and Artemia were searched, scuticocilates were detected both in live and dead rotifer, and at the dregs of culture tank bottoms at almost hatcheries. When rotifer infected with scuticocilates fed on fish larvae, lots of scuticocilate were inhabited at the bottom of fry rearing tanks. After feeding on scuticocilates-infected rotifer on fish larvae, first infection was detected at 10 days after bottom dwelling or 40 days old after hatching. By histopathological examination we confirmed the infection route of eyeball or brain contamination was that the ciliate worms digged through mouth and front part of the dosal fin cuticle, transferred into eyeball along the epithelium and muscle tissue, and reached finally into brain by the muscle and nerve tissue. The infection of internal organs was clarified into two routes. The first route was started from the infection at ventral and anal fin rays by the worms, and reached at the anus and rectum through the epithelium and muscle tissue. The second route was initiated from the infection at urinary organ and reached into the rectum epithelium cells, inner wall of intestine, abdominal cavity, pancreas, kidney, and pancreas. At seed production farms where fish larvae fed on scuticocilate-free rotifer, the worms were not detected not only at the food organisms culture tanks and juvenile rearing tanks but also larval flounder less than 7cm in total length.

• Asian-Australasian Journal of Animal Sciences
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• 제28권4호
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• pp.530-537
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• 2015

The objective of this study was to evaluate the in vitro effects of flavonoid-rich plant extracts (PE) on ruminal fermentation characteristics and methane emission by studying their effectiveness for methanogenesis in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The PE (Punica granatum, Betula schmidtii, Ginkgo biloba, Camellia japonica, and Cudrania tricuspidata) known to have high concentrations of flavonoid were added to an in vitro fermentation incubated with rumen fluid. Total gas production and microbial growth with all PE was higher than that of the control at 24 h incubation, while the methane emission was significantly lower (p<0.05) than that of the control. The decrease in methane accumulation relative to the control was 47.6%, 39.6%, 46.7%, 47.9%, and 48.8% for Punica, Betula, Ginkgo, Camellia, and Cudrania treatments, respectively. Ciliate populations were reduced by more than 60% in flavonoid-rich PE treatments. The Fibrobacter succinogenes diversity in all added flavonoid-rich PE was shown to increase, while the Ruminoccocus albus and R. flavefaciens populations in all PE decreased as compared with the control. In particular, the F. succinogenes community with the addition of Birch extract increased to a greater extent than that of others. In conclusion, the results of this study showed that flavonoid-rich PE decreased ruminal methane emission without adversely affecting ruminal fermentation characteristics in vitro in 24 h incubation time, suggesting that the flavonoid-rich PE have potential possibility as bio-active regulator for ruminants.

• Asian-Australasian Journal of Animal Sciences
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• 제26권9호
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• pp.1289-1294
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• 2013

This study evaluated the in vitro effect of medicinal plant extracts on ruminal methanogenesis, four different groups of methanogens and ruminal fermentation characteristics. A fistulated Holstein cow was used as a donor of rumen fluid. Licorice and mugwort extracts (Glycyrrhiza uralensis and Artemisia capillaris, 0.5% and 1% of total substrate DM, respectively), previously used as folk remedies, were added to an in vitro fermentation incubated with buffered-rumen fluid. Total gas production in Glycyrrhiza uralensis extract treatment was not significantly different between treatments (p<0.05) while total gas production in the Artemisia capillaris extract treatment was lower than that of the control. Artemisia capillaris extract and Glycyrrhiza uralensis extract reduced $CH_4$ emission by 14% (p<0.05) and 8% (p<0.05), respectively. Ciliate-associated methanogens population decreased by 18% in the medicinal plant extracts treatments. Medicinal plant extracts also affected the order Methanobacteriales community. Methanobacteriales diversity decreased by 35% in the Glycyrrhiza uralensis extract treatment and 30% in the Artemisia capillaris extract treatment. The order Methanomicrobiales population decreased by 50% in the 0.5% of Glycyrrhiza uralensis extract treatment. These findings demonstrate that medicinal plant extracts have the potential to inhibit in vitro ruminal methanogenesis.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.54-62
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• 2018

Objective: Due to the threat of global warming, the livestock industry is increasingly interested in exploring how feed additives may reduce anthropogenic greenhouse gas emissions, especially from ruminants. This study investigated the effect of Rhodophyta supplemented bovine diets on in vitro rumen fermentation and rumen microbial diversity. Methods: Cannulated Holstein cows were used as rumen fluid donors. Rumen fluid:buffer (1:2; 15 mL) solution was incubated for up to 72 h in six treatments: a control (timothy hay only), along with substrates containing 5% extracts from five Rhodophyta species (Grateloupia lanceolata [Okamura] Kawaguchi, Hypnea japonica Tanaka, Pterocladia capillacea [Gmelin] Bornet, Chondria crassicaulis Harvey, or Gelidium amansii [Lam.] Lamouroux). Results: Compared with control, Rhodophyta extracts increased cumulative gas production after 24 and 72 h (p = 0.0297 and p = 0.0047). The extracts reduced methane emission at 12 and 24 h (p<0.05). In particular, real-time polymerase chain reaction analysis indicated that at 24 h, ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens decreased at 24 h (p = 0.0002, p<0.0001, and p<0.0001), while Fibrobacter succinogenes (F. succinogenes) increased (p = 0.0004). Additionally, Rhodophyta extracts improved acetate concentration at 12 and 24 h (p = 0.0766 and p = 0.0132), as well as acetate/propionate (A/P) ratio at 6 and 12 h (p = 0.0106 and p = 0.0278). Conclusion: Rhodophyta extracts are a viable additive that can improve ruminant growth performance (higher total gas production, lower A/P ratio) and methane abatement (less ciliateassociated methanogens, Ruminococcus albus and Ruminococcus flavefaciens and more F. succinogenes.

• 환경생물
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• 제28권3호
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• pp.125-132
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• 2010

하계 진해만 16개의 정점에서 해양생태계의 오염 정도를 평가하기 위해서 플랑크톤 건강 지수를 살펴보았다. 해양생태계 건강지수 산출은 부유성 플랑크톤 생물 엔테로박테리아 Escherichia coli, HB, ANF, HNF, HABs 그리고 섬모충류 등과 더불어 무기와 유기 오염원인 DOC, COD, 그리고 Chl.a 등을 각각 조사하였다. 그 중 플랑크톤 지수 산출은 오염압력의 반응에 민감한 Chl.a, HABs, HB, E. coli 등 4개의 지표를 시범적 선정하였다. 또한 점수산정기준은 과거자료를 바탕으로 통계학적 기법으로 해석하였으며, 그들 건강지수 등급도 4개로 나누었다. 그 결과 진해만 해역은 전반적으로 "좋음"의 B등급을 받았다. 본 연구에서 산출한 플랑크톤 건강지수는 진해만의 해양생태계 건강성 평가를 하기 위한 좋은 방법 중 하나로 고려하여도 될 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권12호
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• pp.1864-1872
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• 2019

Objective: This study was conducted to evaluate the effects of Ecklonia stolonifera (E. stolonifera) extract addition on in vitro ruminal fermentation characteristics, methanogenesis and microbial populations. Methods: One cannulated Holstein cow ($450{\pm}30kg$) consuming timothy hay and a commercial concentrate (60:40, w/w) twice daily (09:00 and 17:00) at 2% of body weight with free access to water and mineral block were used as rumen fluid donors. In vitro fermentation experiment, with timothy hay as substrate, was conducted for up to 72 h, with E. stolonifera extract added to achieve final concentration 1%, 3%, and 5% on timothy hay basis. Results: Administration of E. stolonifera extract to a ruminant fluid-artificial saliva mixture in vitro increased the total gas production. Unexpectedly, E. stolonifera extracts appeared to increase both methane emissions and hydrogen production, which is contrasts with previous observations with brown algae extracts used under in vitro fermentation conditions. Interestingly, real-time polymerase chain reaction indicated that as compared with the untreated control the ciliate-associated methanogen and Fibrobacter succinogenes populations decreased, whereas the Ruminococcus flavefaciens population increased as a result of E. stolonifera extract supplementation. Conclusion: E. stolonifera showed no detrimental effect on rumen fermentation characteristics and microbial population. Through these results E. stolonifera has potential as a viable feed supplement to ruminants.